Well fuck, that seems interesting. Intelligent slime with logical reason for running an orphanage and quite fitting ability (as slimes usually can melt/assimilate things so appraising/scanning objects doesn't seem that far off).
Evolving Skelly really surprised me. It would be funny as fuck if the gem got inserted under his ribcage like Papa Bones has it in Overlord.
The confession was weird but kinda expected with how she brought him to her "house" and he met both her sister and "father".
But if I were in his shoes I would search for all sorts of necromancy-related books and people. Learn if you can create undead with their memoires intact (as much as possible of course) and either try to learn the art or find suitable necromancer and bring Rubia back to (un)life!